Supplying liquid to at least one area of a surface to be cleaned

ABSTRACT

In the context of vacuum cleaning, a suction head is provided, which includes a housing that is couplable to an air suction source of a vacuum cleaner, and two brushes in a substantially parallel arrangement in the housing. The brushes are rotatable about a rotation axis and configured to interact with a surface to be cleaned. The suction head is further equipped with a wetting arrangement that enables a direct supply of liquid from at least one liquid supplying position to at least one area of the surface to be cleaned, where the at least one liquid supplying position is in an area between the brushes and at a level of the rotation axes of the brushes or closer to surface level.

FIELD OF THE INVENTION

The invention relates to a suction head configured to be applied in avacuum cleaner and to perform a cleaning action on a surface, thesuction head comprising: a housing that includes a coupling areaconfigured to enable coupling of the housing to an air suction source ofthe vacuum cleaner, and two brushes in a substantially parallelarrangement in the housing, wherein each of the brushes is rotatableabout a rotation axis and is configured to interact with the surface tobe cleaned.

Further, the invention relates to a cordless vacuum cleaner comprising asuction head as mentioned.

BACKGROUND OF THE INVENTION

Vacuum cleaners are known for removing dirt from a surface to becleaned. The term “dirt” as used in the present text is to be understoodso as to cover any contamination as may be present on a surface and thatcan be removed under the influence of a vacuum cleaning action, probablycombined with another cleaning action such as mopping. Practicalexamples in this respect include dust and small particles of any kind,and also wet types of contamination such as spilled drinks. A practicalexample of the surface to be cleaned is a floor, wherein the floor maybe of any kind, such as a wooden floor, a carpet floor, a tile floor,etc.

Generally, a vacuum cleaner has a vacuum cleaner head or suction head,which is the part of the vacuum cleaner where the actual process ofpicking up dirt from a surface to be cleaned is to take place and whichis therefore to be put on or at least close to the surface. Further, avacuum cleaner normally comprises a body portion including a dirtaccumulating area, and an arrangement configured to act on the suctionhead so that a suction force is prevailing in the suction head duringoperation of the vacuum cleaner. The suction force serves to facilitatetransport of dirt that is picked up from the surface during operation ofthe vacuum cleaner towards the dirt accumulating area, wherein the dirtis made to pass an outlet opening in a housing of the suction head. Thesuction force may also have a function in the actual process of pickingup the dirt from the surface. On the other hand, the suction head may beequipped with at least one movable component for interacting with thesurface in order to pick up the dirt, such as at least one rotatablebrush that may serve as an agitator of the dirt and that mayparticularly be configured to help dislodge dirt from the surface anddirect it towards the outlet opening.

WO 2011/083373 A1 discloses a cleaning device for removing particlesfrom a surface, comprising spraying means for spraying droplets of awork fluid, a rotatable brush having flexible brush elements, an inletfor receiving dirtied air such as air laden with particles, and acleansing unit. The cleansing unit is suitable for separating at least aportion of the droplets of work fluid from the air. During operation,the rotatable brush is wetted by the work fluid. The brush is of such adimension and is rotated at such a rotational speed that the droplets ofthe work fluid are expelled as a mist of droplets from the flexiblebrush elements into a coalescing space of the device. The dirtied airreceived by the inlet is receivable by the coalescing space, to formcoalesced particles of the droplets expelled from the brush elements andparticles in the dirtied air, the coalesced particles being conveyablefrom the coalescing space to the cleansing unit.

WO 2012/107876 A1 discloses a cleaning device comprising a head havingan open side for facing surfaces to be cleaned, and at least one brushfor contacting surfaces to be cleaned, which is rotatably arranged inthe head. The at least one brush is provided with a plurality of brushhairs, wherein it is possible that these brush hairs are extremely softand flexible. In such a case, a cleaning action of a surface is notperformed by scrubbing the surface but by putting the brush hairsalternately in and out of contact with the surface during rotation ofthe brush. In particular, during one revolution of the brush, the brushhairs remove particles and/or liquid droplets from a soiled surface andfling away the particles and/or the droplets when they reach a positionin which they are free from contact to the surface and in which they canbe fully outstretched. In the head of the cleaning device, in which thebrush is arranged, there are means for receiving the particles and/orthe droplets, and for possibly transporting the particles and/or thedroplets towards a space where they are collected. The cleaning devicemay be equipped with means for realizing a suction force at the head inorder to direct the particles and/or the droplets in a desired directiononce they are released from the brush hairs. Further, it is possiblethat the cleaning device is configured to supply a cleaning liquid tothe rotating brush in order to promote the adherence of particles to thebrush hairs and/or to realize an additional cleaning effect on a surfaceto be cleaned.

WO 2017/071727 A1 discloses a vacuum cleaner head comprising a housinghaving a vacuum extraction zone and first and second rollers configuredto locate against a surface to be cleaned, wherein each of the first andsecond rollers is configured to pick-up dirt from the surface and carrythe dirt to the vacuum extraction zone in the housing of the vacuumcleaner head when being rotated and moved over the surface duringoperation. The vacuum extraction zone is defined between the outletopening and the first and second rollers. When the vacuum cleaner headis used in a vacuum cleaner and the vacuum cleaner is operated, anairflow is generated through the vacuum extraction zone to the outletopening. The vacuum cleaner head may further comprise a liquid dispenserto dispense a liquid onto the surface to be cleaned, and the vacuumcleaner head may further comprise a liquid dispenser to dispense aliquid onto at least one of the first and second rollers. Therefore, itis possible to dampen a surface to be cleaned to promote the removal ofdetritus from the surface.

SUMMARY OF THE INVENTION

In general, it is an object of the invention to provide measures aimedat achieving good cleaning results of a vacuum cleaning action performedon a surface. Further, it is an object of the invention to providemeasures aimed at preventing pollution of the suction head.

In view of the foregoing, the invention provides a suction headconfigured to be applied in a vacuum cleaner and to perform a cleaningaction on a surface, the suction head comprising: a housing thatincludes a coupling area configured to enable coupling of the housing toan air suction source of the vacuum cleaner, two brushes in asubstantially parallel arrangement in the housing, wherein each of thebrushes is rotatable about a rotation axis and is configured to interactwith the surface to be cleaned, and a wetting arrangement that isarranged and configured to enable a direct supply of liquid from atleast one liquid supplying position to at least one area of the surfaceto be cleaned, wherein the at least one liquid supplying position is inan area between the brushes and at a level of the rotation axes of thebrushes or closer to surface level.

It follows from the foregoing definition of the suction head accordingto the invention that the invention involves equipping the suction headwith a wetting arrangement that is arranged and configured to enable adirect supply of liquid from at least one liquid supplying position toat least one area of the surface to be cleaned, and that the at leastone liquid supplying position is chosen so as to be in an area betweenthe brushes and at a level of the rotation axes of the brushes or closerto surface level. In this way, it is achieved that the surface to becleaned is wetted in a controlled fashion, wherein the brushes arewetted in an indirect fashion through contact to the surface so that itis not necessary to have a direct supply of liquid to the brushes,although this is not excluded in the context of the invention. As thesuction head is normally moved back and forth on the surface to becleaned by a user, having a supply of liquid at a position that isbetween the brushes is sufficient and effective to realize a wetcondition of both brushes. By having the at least one liquid supplyingposition at a level of the rotation axes of the brushes or closer tosurface level, it is achieved that a bottom side of the suction head caneffectively be cleaned by clear liquid. It is practical if the directsupply of liquid to the at least one area of the surface to be cleanedinvolves a continuous or intermittent flow of liquid, or spray ofliquid, directed from the at least one liquid supplying position on thesuction head towards the at least one area. The wetting arrangement canbe provided more or less as an add-on to an existing design of a suctionhead, but it is also possible that the wetting arrangement is providedin a more integrated fashion. A practical example of the liquid is wateror a mixture of water and a cleaning agent.

In the context of the invention, it is possible that the at least oneliquid supplying position is at a bottom surface portion of the suctionhead that is arranged and configured to face the surface to be cleanedat a distance of at least 2 mm and at most 6 mm to the surface. In thatway, a cleaning effect on the bottom surface portion may be obtained,following from the bottom surface portion not being exposed to the dirt11 that is flung away by the brushes 20 and a possibility that liquidbridges the distance by surface tension. Keeping the bottom surfaceportion clean is a way of preventing pollution of the suction head andis thereby also helpful in optimizing cleaning results of the surface tobe cleaned as there can be no contaminating effect of a clean surfaceportion of the suction head on the surface.

In a practical embodiment of the suction head according to theinvention, the wetting arrangement is arranged and configured to enablea direct supply of liquid from at least two liquid supplying positionsdistributed over the suction head in the direction in which the rotationaxes of the brushes extend. Having the distribution of the liquidsupplying positions as mentioned is a factor in achieving that thebrushes are sufficiently wetted, without any dry or nearly-dry areaswhich might render the cleaning action less effective.

According to an advantageous option, the suction head comprises anelongated intermediate component that is located in an area between thebrushes and that optionally comprises two portions configured to coverportions of the brushes. It is practical if, at the position of a topside thereof, the elongated intermediate component is suspended from aportion of the housing of the suction head. Covering as much as possibleof the brushes, preferably at a very close range, is beneficial when itcomes to effectively invoking the suction force in the suction head. Theelongated intermediate component may be an integral part of the housingor may be provided as a separate component that could be removablycoupled to another component of the housing so as to allow repair orcleaning, for example. On the one hand, the presence of the elongatedintermediate component in the suction head disables a known optionaccording to which the one brush wets the other brush during operation,but on the other hand, the elongated intermediate component may have afunction in facilitating liquid supply, and also in preventing pollutionof internal surfaces of the suction head. In particular, it is possiblethat the at least one liquid supplying position is at a bottom surfaceportion of the elongated intermediate component that is arranged andconfigured to face the surface to be cleaned. When this bottom surfaceportion of the elongated intermediate component is arranged so as to beclose to the surface to be cleaned, i.e. when this bottom surfaceportion is arranged and configured to face the surface to be cleaned ata distance of at least 2 mm and at most 6 mm to the surface as suggestedearlier, the above-described cleaning effect is realized on this bottomsurface portion.

It is practical if the wetting arrangement comprises a conduit systemconfigured to transport liquid and to let out liquid at the at least oneliquid supplying position. In the case that the suction head comprisesthe above-mentioned elongated intermediate component, it may be so thatthe conduit system comprises at least one conduit extending through theelongated intermediate component. Especially when the wettingarrangement is arranged and configured to enable a direct supply ofliquid from two or more liquid supplying positions to two or more areasof the surface to be cleaned, it may be advantageous if theabove-mentioned conduit system comprises at least one main conduit andat least one branch conduit that is coupled to the at least one mainconduit and that extends from the at least one main conduit towards theat least one liquid supplying position. In such a case, the main conduitmay serve as a kind of buffer and/or distributor of the liquid. In orderto control the flow of liquid from the at least one main conduit to theat least one branch conduit, it may be helpful if a restricted liquidpassage is present at an interface of the at least one main conduit andthe at least one branch conduit. In an embodiment of the suction head inwhich the option that the suction head comprises the elongatedintermediate component and that at least one conduit of the conduitsystem extends through the elongated intermediate component is combinedwith the option that the conduit system comprises at least one mainconduit and at least one branch conduit, it may typically be so that theat least one branch conduit is the at least one conduit extendingthrough the elongated intermediate component.

In an advantageous embodiment, the suction head comprises a restrictionelement in fluid communication with the at least one main conduit andthe at least one branch conduit, wherein the restriction element isprovided with at least one restriction opening configured to allowliquid to pass in a direction from the at least one main conduit towardsthe at least one branch conduit. In this embodiment, it may be so thatthe restriction element or an assembly of components in which therestriction element is included is removably arranged in the suctionhead. This allows for easy cleaning of the restriction element in orderto avoid clogging of the at least one restriction opening of therestriction element.

The wetting arrangement can be used for other purposes besides supplyingliquid to at least one area of the surface to be cleaned. For example,assuming that the suction head comprises at least one wheel that isrotatably arranged on the suction head and that is configured to be incontact with the surface to be cleaned, it is possible that the wettingarrangement is further arranged and configured to enable a direct supplyof liquid to the at least one wheel. A notable advantage of this optionis that cleaning of the at least one wheel can take place automatically,without a need for action from the side of the user and without a needfor external cleaning tools nor tools for dismantling the components ofthe suction head. Thus, a very reliable way of keeping the at least onewheel of the suction head clean is provided, whereby a situation inwhich the at least one wheel might be of influence on the cleaningresult is avoided. In particular, the wetting arrangement may bearranged and configured to enable a direct supply of liquid to the atleast one wheel at the position of the tread of the at least one wheel,from outside of the at least one wheel. In that case, the at least onewheel can simply be of conventional design and made up of one or moreconventional materials such as plastic and rubber, and the at least onewheel can be mounted in the suction head in any suitable known way. Therotating movement of the wheel can be used to advantage when it comes tospreading the liquid over the entire tread of the wheel. An additionalmeasure aimed at keeping the at least one wheel clean involves arrangingthe at least one wheel so that the rotating brushes are enabled tointeract with the wheel during operation of the suction head. A furthereffect of this measure may be that portions of the brushes which is nearthe wheel is wetted to some extent by the wheel. In any case, it may beso that the at least one wheel is located in an area between thebrushes.

In the context of the invention, the brushes may be of any type that issuitable to be used for picking up dirt from a surface to be cleaned,wherein the brushes may be chosen to be either identical or different.Each of the brushes may especially be designed to serve as an agitator,for example, agitating dirt particles as may be present on the surface.In a practical embodiment of the suction head according to theinvention, at least one of the brushes comprises a core element andflexible microfiber elements arranged on the core element. In such abrush, a linear mass density lower than 150 g per 10 km may beapplicable to the microfiber elements, or at least tip portions thereof,so that the microfiber elements really can be highly flexible. Thelinear mass density as mentioned may even be lower than 10 g per 10 km,5 g per 10 km or 1 g per 10 km. Such microfiber elements can be placedon the core element in a dense arrangement so as to very effectivelyinteract with a surface to be cleaned during operation of the suctionhead. Further, it may be practical if such microfiber elements arearranged on the core element in tufts.

It is practical if an operational shape of both brushes is generally theshape of a cylinder having a circular periphery, in other words, if theoperational shape of the brushes is generally the shape of a roller,which may be an elongated roller.

The invention further relates to a vacuum cleaner, particularly acordless vacuum cleaner, comprising a suction head as defined anddescribed in the foregoing, which is equipped with a wetting arrangementthat is arranged and configured to enable a direct supply of liquid fromat least one liquid supplying position to at least one area of a surfaceto be cleaned. It is practical if such a vacuum cleaner comprises areservoir that is configured to receive liquid, to contain liquid, andto let out liquid to the wetting arrangement of the suction head.Advantageously, the reservoir is removably arranged on the vacuumcleaner so that it is easy for a user to take the reservoir to a placewhere the reservoir can be filled with liquid.

The above-described and other aspects of the invention will be apparentfrom and elucidated with reference to the following detailed descriptionof a practical embodiment of a suction head comprising a housing and twobrushes arranged in the housing, and further comprising a wettingarrangement that is arranged and configured to enable a direct supply ofliquid from at least one liquid supplying position to at least one areaof a surface to be cleaned.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in greater detail with reference tothe figures, in which equal or similar parts are indicated by the samereference signs, and in which:

FIG. 1 diagrammatically shows components of a wet vacuum cleaneraccording to an embodiment of the invention and a portion of a floorhaving a surface to be cleaned,

FIG. 2 diagrammatically shows a view of a longitudinal section of asuction head according to an embodiment of the invention, taken at aposition between two brushes which are included in the suction head,

FIG. 3 shows an enlarged detail of FIG. 2 ,

FIG. 4 diagrammatically shows a perspective top view of a portion of thesuction head,

FIGS. 5 and 6 diagrammatically show views of a cross-section of thesuction head, taken at different longitudinal positions on the suctionhead,

FIG. 7 shows an enlarged detail of FIG. 6 , and

FIG. 8 illustrates an optional set-up of a conduit system of a wettingarrangement that is included in the suction head.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 illustrates the design of a wet vacuum cleaner 100 according toan embodiment of the invention. The particular vacuum cleanerrepresented in FIG. 1 and described in the following is just one exampleof many types of vacuum cleaners which are feasible in the framework ofthe invention. In this respect, it is noted that the invention does notonly relate to wet vacuum cleaners, but also to other types of vacuumcleaners such as wet/dry vacuum cleaners having a dry cleaning functionbesides a wet cleaning function.

The wet vacuum cleaner 100 is configured to be used for the purpose ofsubjecting a surface 10 such as a floor surface to a wet cleaningaction. FIG. 1 shows the vacuum cleaner 100 in a normal, operationalorientation relative to the surface 10 to be cleaned. The use in thepresent text of a term having an orientation aspect is to be understoodin relation to this normal, operational orientation of the vacuumcleaner 100 relative to the surface 10 to be cleaned, wherein it isassumed that the surface 10 is at a bottom position and the vacuumcleaner 100 is placed on the surface 10.

At a side that is supposed to face the surface 10 during operation ofthe vacuum cleaner 100, the vacuum cleaner 100 comprises a suction head101 accommodating two brushes 20 which are configured to interact withthe surface 10 during operation of the vacuum cleaner 100. In thefollowing, it is assumed that each of the brushes 20 is provided in theform of a roller that is rotatable about a rotation axis 21 that isdefined by a central longitudinal axis of the roller, and that each ofthe brushes 20 comprises a core element 22 and flexible microfiberelements 23 arranged on the core element 22, which does not alter thefact that other embodiments of the brushes 20 are possible as well. Thebrushes 20 may be identical, but this is not necessary in the context ofthe invention. As indicated in FIG. 1 by means of curved arrows depictedat the position of the brushes 20, the brushes 20 are arranged so as tobe rotatable in opposite directions with respect to each other abouttheir respective rotation axes 21. The suction head 101 comprises ahousing 30 that is configured to partially cover the brushes 20. Thehousing 30 can be made of a plastic material, for example.

Besides the suction head 101, the vacuum cleaner 100 comprises a bodyportion 102 that is configured to be taken hold of by a user of thevacuum cleaner 100. Preferably, the suction head 101 and the bodyportion 102 are removably couplable to each other. The body portion 102can be shaped in any appropriate way. The outline of the body portion102 as shown in FIG. 1 is of a diagrammatical nature only. It ispractical if the body portion 102 comprises a handle so that a user caneasily take hold of the body portion 102 and move the vacuum cleaner 100across the surface 10 to be cleaned as desired.

For the purpose of driving the brushes 20 during operation of the vacuumcleaner 100, the vacuum cleaner 100 is equipped with a suitable electricdrive mechanism (not shown). For the purpose of powering the drivemechanism and probably also other components of the vacuum cleaner 100,the vacuum cleaner 100 may be connectable to the mains and/or may beequipped with a suitable battery arrangement. Preferably, the vacuumcleaner 100 is a cordless device comprising a rechargeable batteryarrangement, in which case it may further be practical if the vacuumcleaner 100 is part of a set including a charging dock besides thevacuum cleaner 100. Such a set may also include a flushing tray that canbe used for the purpose of cleaning the brushes 20. In case the vacuumcleaner 100 is not equipped with a battery, a simple dock that iswithout charging ability may be provided for receiving and holding thevacuum cleaner 100 while the vacuum cleaner 100 is not being operated.

The body portion 102 of the vacuum cleaner 100 includes a liquidreservoir 40 that serves for containing a liquid such as water or amixture of water and a cleaning agent, and a liquid supply mechanism 41that serves for supplying the liquid to a wetting arrangement 42 of thesuction head 101 during operation of the vacuum cleaner 100. The liquidsupply mechanism 41 may comprise any suitable type of pump arrangement,for example, or may be configured to enable displacement of the liquidas desired under the influence of gravity. In the shown example, thewetting arrangement 42 of the suction head 101 is configured to enableboth a direct supply of liquid to areas of the surface 10 to be cleanedand a direct supply of liquid to two wheels 90 of the suction head 101(see FIGS. 2, 3, 5 and 6 ), as will be explained later in more detail.Further, in the shown example, the suction head 101 comprises anelongated intermediate component 25 that is located in an area 24between the brushes 20 and that comprises two concavely curved portionsconfigured to cover portions of the brushes 20, and the wettingarrangement 42 comprises a conduit system 43 that is partially arrangedin the elongated intermediate component 25 and that is configured totransport the liquid and to let out the liquid to the areas of thesurface 10 and to the two wheels 90. In FIG. 1 , the liquid reservoir40, the liquid supply mechanism 41 and the wetting arrangement 42 of thesuction head 101 are indicated by means of dotted lines. It is practicalif the liquid reservoir 40 is removably coupled to the body portion 102so that a user is enabled to separate the liquid reservoir 40 from thebody portion 102 when it is desired to take the liquid reservoir 40 to aplace where the liquid reservoir 40 is to be filled with liquid.

The body portion 102 of the vacuum cleaner 100 further includes a dirtreservoir 50 that serves for receiving and accumulating wet dirt 11 thatis picked up from the surface 10 by the brushes 20 during operation ofthe vacuum cleaner 100. The dirt reservoir 50 can be configured innumerous ways as conventionally available for accumulating wet dirt fromthe incoming dirt 11 that is picked up from the surface 10 such as forinstance a cyclonic arrangement or a tube-in-cup arrangement. The bodyportion 102 includes a vacuum mechanism 60 configured to createunderpressure that is functional to enable transport of the dirt 11 fromthe area where the brushes 20 are located to the dirt reservoir 50 inthe body portion 102, through an outlet opening 31 in a surface 32 ofthe housing 30 facing the brushes 20 and a suction channel 51 extendingfrom the outlet opening 31 to the dirt reservoir 50. As can be seen inthe view of the portion of the suction head 101 in FIG. 4 , the housing30 includes a coupling area 33 that is configured to enable coupling ofthe housing 30 to the assembly of the suction channel 51, the dirtreservoir 50 and the vacuum mechanism 60 in the body portion 102 of thevacuum cleaner 100. The outlet opening 31 is in fluid communication withthis coupling area 33.

Basic aspects of the way in which the wet vacuum cleaner 100 is operatedare as follows. During operation, the brushes 20 are driven so as torotate and the liquid supply mechanism 41 is activated so as to supplyliquid to the wetting arrangement 42 of the suction head 101 so thatliquid may be let out to the surface 10 to be cleaned and to the twowheels 90. Any stains as may be present on an area of the surface 10that is within reach of the brushes 20 are detached under the influenceof the liquid and agitation by the brushes 20, and dirt particles anddust as may be present on the area of the surface 10 are removed alongwith the liquid and conveyed to the dirt reservoir 50, passing throughthe outlet opening 31 and the suction channel 51 in the process. Thedirt 11 is picked up from the surface 10 by tip portions of themicrofiber elements 23 of the brushes 20 and is flung away from the tipportions as the brushes 20 rotate, at a position where the tip portionsmove out of contact to the surface 10.

As illustrated in FIG. 1 , the vacuum cleaner 100 may be equipped with auser interface 70, which user interface 70 may include an on/off button71, for example. The vacuum cleaner 100 may further comprise acontrolling system 80 including a microcontroller that is programmed toput the brushes 20 in motion and to activate both the liquid supplymechanism 41 and the vacuum mechanism 60 in reaction to input receivedfrom the user through the user interface 70 to that end.

FIGS. 2-8 serve to illustrate aspects of a suction head 101 according toan embodiment of the invention, especially aspects of the wettingarrangement 42 of the suction head 101. It can be seen in FIGS. 2 and 4that the conduit system 43 of the wetting arrangement 42 comprises twomain conduits 44, 45 which are located in different halves of thesuction head 101 as seen in a longitudinal direction l being thedirection which the rotation axes 21 of the brushes 20 extend, and whichare couplable to the liquid supply mechanism 41. Further, the conduitsystem 43 comprises four branch conduits 46, 47, 48, 49, namely, as seenfrom left to right in FIG. 2 , i) a branch conduit 46 that is coupled toa first one 44 of the main conduits 44, 45, that is configured to letout liquid to one of the wheels 90, and that extends from the first one44 of the main conduits 44, 45 to the wheel 90, ii) a branch conduit 47that is also coupled to the first one 44 of the main conduits 44, 45, ata longitudinal position more or less between the wheel 90 and the outletopening 31, that is configured to let out liquid to a first area of thesurface 10 to be cleaned, and that extends from the first one 44 of themain conduits 44, 45 to the surface 10, iii) a branch conduit 48 that iscoupled to a second one 45 of the main conduits 44, 45, at alongitudinal position more or less between another wheel 90 and theoutlet opening 31, that is configured to let out liquid to a second areaof the surface 10 to be cleaned, and that extends from the second one 45of the main conduits 44, 45 to the surface 10, and iv) a branch conduit49 that is also coupled to the second one 45 of the main conduits 44,45, that is configured to let out liquid to the other wheel 90, and thatextends from the second one 45 of the main conduits 44, 45 to the wheel90.

The branch conduits 47, 48 which are configured to let out liquid to thesurface 10 to be cleaned are arranged to partially extend through theelongated intermediate component 25, and the liquid supplying positionswhere the liquid is let out to the surface 10 are at a bottom side ofthe elongated intermediate component 25, i.e. at a bottom surfaceportion 26 of the elongated intermediate component 25 that is arrangedand configured to face the surface 10 to be cleaned. In this respect, itis noted that in general, in the context of the invention, the liquidsupplying positions where the liquid is let out to the surface 10 are ata level of the rotation axes 21 of the brushes 20 or closer to surfacelevel, i.e. at the level of the rotation axes 21 of the brushes 20 or ata lower level.

Letting out liquid to the surface 10 at liquid supplying positions whichare distributed along the brushes 20 in the longitudinal direction I isa factor in achieving that the brushes 20 are sufficiently wetted,without any dry or nearly-dry areas which might render the cleaningaction less effective. Letting out liquid to the wheels 90 duringoperation of the suction head 101 results in keeping the wheels 90 wetand clean, so that any negative influences on the results of the actionof cleaning the surface 10 following from the fact that the surface 10is contacted by the wheels 90 are avoided. It can be seen in FIGS. 2 and3 that the position at which the liquid is let out to a wheel 90 is aposition right above the wheel, such that the liquid can be received bythe wheel 90 at the position of the tread 91 thereof.

FIG. 5 shows another advantageous aspect of the design of the suctionhead 101 according to the embodiment of the invention, which resides inthe fact that each of the two wheels 90 is arranged so as to be incontact with the brushes 20, especially with the microfiber elements 23of the brushes 20. In the first place, this contributes to keeping thewheels 90 clean. In the second place, this contributes to realizing thatthe brushes 20 are wetted along their length, i.e. their dimension inthe longitudinal direction I.

FIG. 6 illustrates the advantageous option of the at least one liquidsupplying position for letting out liquid to the surface 10 to becleaned being at a bottom surface portion of the suction head 101 thatis arranged and configured to face the surface 10 at a distance of atleast 2 mm and at most 6 mm to the surface 10. By having only a smallspace between the surface 10 and the bottom surface portion of thesuction head 101, it is achieved that the bottom surface portion of thesuction head 101 is effectively kept clean. It is practical if thebottom surface portion of the suction head 101 that is arranged andconfigured to face the surface 10 at the relatively small distance tothe surface 10 as mentioned comprises the bottom surface portion 26 ofthe elongated intermediate component 25.

On the basis of the foregoing, an overview of the advantageous aspectsof the small space between the surface 10 to be cleaned and the bottomsurface portion of the suction head 101 is provided:

-   -   The liquid beneath the bottom surface portion bridges with the        surface 10 and cleans the bottom surface portion by means of the        surface tension, capturing small dirt particles that could        adhere to the bottom surface portion.    -   The flow of clean liquid from the different positions at which        the liquid is let out has a direct cleaning effect on the bottom        surface portion, especially on the bottom side of the elongated        intermediate component 25.    -   The movement of the suction head 101 results in the area        underneath the bottom surface portion being in constant        interaction with the brushes 20.

It is further noted that it is advantageous if the surface 32 of thehousing 30 facing the brushes 20 is arranged so as to cover the brushes20 at only a minimal distance, as in that case, the suction force iseffectively invoked in the suction head 101, as a result of which airspeed along the surface 32 can be relatively high, which alsocontributes to keeping the surface 32 clean, besides the fact that thereis practically no room where dirt might build up.

In order to promote equal distribution of the liquid over the respectivebranch conduits 46, 47, 48, 49, it is practical if a restricted liquidpassage 27 is present at an interface of the main conduits 44, 45 andthe respective branch conduits 46, 47, 48, 49, as can best be seen inFIG. 7 . The fact is that the restricted liquid passages 27 function toprevent drainage of the main conduits 44, 45 at the position of thebranch conduit 47, 48 that comes first as seen in a downstreamdirection, which would hamper the supply of fluid to the other branchconduit 46, 49. Hence, on the basis of the presence of the restrictedliquid passages 27, controlled retrieval of liquid from the mainconduits 44, 45 at the positions where the branch conduits 46, 47, 48,49 are coupled to the main conduits 44, 45 is realized.

FIG. 8 illustrates an option according to which a main conduit 44 ismore or less dimensioned so as to serve as a buffer of the liquid 15,and according to which a restriction element 28 is applied at theposition where the respective branch conduits 46, 47 are coupled to themain conduit 44. In the shown example, the restriction element 28comprises a strip that is provided with two restriction openings. Therestriction openings are dimensioned so as to realize restricted liquidpassages 27 which are configured to create a flow of droplets of theliquid 15 rather than a continuous flow. Preferably, the restrictionelement 28 or an assembly of components in which the restriction element28 is included is removably arranged in the suction head 101 so that therestriction element 28 or the entire assembly may be removed by a userfrom time to time for cleaning purposes. Cleaning the restrictionelement 28 and possibly also adjoining components on a regular basis mayespecially be helpful in avoiding that the restriction openings getclogged and that the supply of liquid 15 to the wheels 90 and thesurface 10 to be cleaned is thereby hindered.

Although both the option of directly supplying liquid 15 to at least onearea of the surface 10 to be cleaned and the option of directlysupplying liquid 15 to the at least one wheel 90 are illustrated andexplained in the context of a single embodiment of the suction head 101according to the invention, it is to be understood that the options canbe applied independently. Further, it is noted that additionally oralternatively to the option of directly supplying liquid 15 to the atleast one wheel 90, an option of directly supplying liquid 15 to aposition in the suction head 101, such as a position on one or both ofthe brushes 20, is feasible in the context of the invention. Generallyspeaking, the wetting arrangement 42 may be realized in any suitableway. For instance, it is possible to design the wetting arrangement 42with a functionality to temporarily stop the supply of liquid to the atleast one wheel 90 if so desired. This may be useful in view of asituation in which a type of surface 10 to be cleaned requires more thanan average amount of liquid, this may allow a user to manually initiatea cleaning action of the at least one wheel 90 from time to time, etc.

When the suction head 101 comprises an elongated intermediate element 25covering a portion of the brushes 20 from the bottom side of the suctionhead 101, as is the case in the shown embodiment of the suction head101, it may be beneficial to use the elongated intermediate element 25to accommodate at least a portion of one or more conduits of a conduitsystem 43 of the wetting arrangement 42, but this is not essential inthe context of the invention.

It will be clear to a person skilled in the art that the scope of theinvention is not limited to the examples discussed in the foregoing, butthat several amendments and modifications thereof are possible withoutdeviating from the scope of the invention as defined in the attachedclaims. It is intended that the invention be construed as including allsuch amendments and modifications insofar they come within the scope ofthe claims or the equivalents thereof. While the invention has beenillustrated and described in detail in the figures and the description,such illustration and description are to be considered illustrative orexemplary only, and not restrictive. The invention is not limited to thedisclosed embodiments. The drawings are schematic, wherein details whichare not required for understanding the invention may have been omitted,and not necessarily to scale.

Variations to the disclosed embodiments can be understood and effectedby a person skilled in the art in practicing the claimed invention, froma study of the figures, the description and the attached claims. In theclaims, the word “comprising” does not exclude other steps or elements,and the indefinite article “a” or “an” does not exclude a plurality. Anyreference signs in the claims should not be construed as limiting thescope of the invention.

Elements and aspects discussed for or in relation with a particularembodiment may be suitably combined with elements and aspects of otherembodiments, unless explicitly stated otherwise. Thus, the mere factthat certain measures are recited in mutually different dependent claimsdoes not indicate that a combination of these measures cannot be used toadvantage.

The terms “comprise” and “include” as used in this text will beunderstood by a person skilled in the art as covering the term “consistof”. Hence, the term “comprise” or “include” may in respect of anembodiment mean “consist of”, but may in another embodiment mean“contain/have/be equipped with at least the defined species andoptionally one or more other species”.

Notable aspects of the invention are summarized as follows. In thecontext of vacuum cleaning, a suction head 101 is provided, which is ofthe type comprising: a housing 30 that is couplable to an air suctionsource 60 of a vacuum cleaner 100, and two brushes 20 in a substantiallyparallel arrangement in the housing 30, wherein each of the brushes 20is rotatable about a rotation axis 21 and is configured to interact witha surface 10 to be cleaned. The suction head 101 is further equippedwith a wetting arrangement 42 that is arranged and configured to enablea direct supply of liquid 15 from at least one liquid supplying positionto at least one area of the surface 10 to be cleaned, wherein the atleast one liquid supplying position is in an area 24 between the brushes20 and at a level of the rotation axes 21 of the brushes 20 or closer tosurface level.

1. A suction head configured to be applied in a vacuum cleaner and toperform a cleaning action on a surface to be cleaned, the suction headcomprising: a housing that includes a coupling area configured to enablecoupling of the housing to an air suction source of the vacuum cleaner,two brushes in a substantially parallel arrangement in the housing,wherein each of the two brushes is rotatable about a rotation axis andis configured to interact with the surface to be cleaned, and a wettingarrangement that is arranged and configured to enable a direct supply ofliquid from at least one liquid supplying position to at least one areaof the surface to be cleaned, wherein the at least one liquid supplyingposition is in an area between the two brushes and at a level of therotation axes of the two brushes or closer to surface level.
 2. Thesuction head according to claim 1, wherein the at least one liquidsupplying position is at a bottom surface portion of the suction head,and wherein the atleast liquid supplying position is arranged andconfigured to face the surface to be cleaned at a distance of at least 2mm and at most 6 mm to the surface.
 3. The suction head according toclaim 1, wherein the wetting arrangement is arranged and configured toenable the direct supply of liquid from at least two liquid supplyingpositions distributed over the suction head in a direction (l) in whichthe rotation axes of the two brushes extend.
 4. The suction headaccording to claim 1, further comprising an elongated intermediatecomponent that is located in the area between the two brushes and thatoptionally comprises two portions configured to cover portions of thetwo brushes.
 5. The suction head according to claim 4, wherein theelongated intermediate component, at the position of a top side thereof,is suspended from a portion of the housing.
 6. The suction headaccording to claim 4, wherein the at least one liquid supplying positionis at a bottom surface portion of the elongated intermediate component,and wherein the bottom surface portion of the elongated intermediatecomponent is arranged and configured to face the surface to be cleaned.7. The suction head according to claim 6, wherein the wettingarrangement comprises a conduit system configured to transport thedirect supply of liquid and to let out the direct supply of liquid atthe at least one liquid supplying position.
 8. The suction headaccording to claim 7, wherein the conduit system comprises at least oneconduit extending through the elongated intermediate component.
 9. Thesuction head according to claim 7, wherein the conduit system comprisesat least one main conduit and at least one branch conduit, and whereinthe at least one branch conduit is coupled to the at least one mainconduit and extends from the at least one main conduit towards the atleast one liquid supplying position.
 10. The suction head according toclaim 9, comprising a restriction element in fluid communication withthe at least one main conduit and the at least one branch conduit,wherein the restriction element is provided with a restriction openingconfigured to allow the direct supply of liquid to pass in a directionfrom the at least one main conduit towards the at least one branchconduit, and wherein the restriction element or an assembly ofcomponents in which the restriction element is included is removablyarranged in the suction head.
 11. The suction head according to claim 1,comprising at least one wheel that is rotatably arranged on the suctionhead, wherein the at least one wheel is configured to be in contact withthe surface to be cleaned, and wherein the wetting arrangement isfurther arranged and configured to enable the direct supply of liquid tothe at least one wheel.
 12. The suction head according to claim 11,wherein the wetting arrangement is arranged and configured to enable thedirect supply of liquid to the at least one wheel at the position of atread of the at least one wheel, from outside of the at least one wheel.13. The suction head according to claim 11, wherein the at least onewheel is arranged so that the two rotating brushes are enabled tointeract with the wheel during operation of the suction head.
 14. Thesuction head according to claim 11, wherein the at least one wheel islocated in the area between the two brushes.
 15. Cordless A cordlessvacuum cleaner, comprising the suction head of claim 1.